How do I know if my gas grill burners are clogged?

Light the grill on high with the grates and heat tents off and look at the flame pattern. Healthy burners show a continuous ring of blue flames with small yellow tips, evenly spaced along the whole tube. Clogged burners show dark gaps where no flame appears, flames leaning or shooting sideways from one hole, mostly yellow lazy flames, or one section of the grill running far cooler than the rest. A grill that takes several attempts to light on one burner is usually clogged as well.

What do you use to clean gas grill burner ports?

A stiff wire is the correct tool — an opened paperclip, a soft brass welding brush wire, or a purpose-made burner port cleaning tool. Push it into each port to break the crust, then withdraw it. Do not drill the holes or force in anything oversized, because enlarging a port permanently changes the gas and air mixture at that spot and creates a hot streak. A stiff nylon or brass brush run along the length of the tube clears the surface debris after.

Should you clean burner tubes with water?

Only if you are prepared to dry them completely. Removable burner tubes can be soaked in warm soapy water and scrubbed, which is effective on greasy buildup, but they must be shaken out and left in the sun or blown out with compressed air until bone dry before reinstalling. Water left inside a burner tube causes internal rust that clogs it again within weeks, and can put out the flame or cause dangerous delayed ignition. Never spray water into burners that are still installed.

Why is one burner on my grill not lighting?

In order of likelihood: clogged ports on that tube, an obstruction in the venturi where the burner meets the gas valve, a failed igniter electrode for that burner, or a burner that has rusted through and is venting gas below where the spark reaches. Spider and insect nests inside the venturi tube are a genuinely common cause and a known safety issue that manufacturers warn about, because a blocked venturi can push flame back into the valve area rather than out the ports.

When should you replace gas grill burners instead of cleaning them?

Replace when a tube has holes rusted through anywhere other than the ports, when it is deformed or cracked, when a whole section of ports will not clear no matter what you do, or when the metal flexes and flakes when you handle it. Stainless steel burners typically last five to ten years and aluminized steel three to five, so if your grill is in that window and the flames are still wrong after a thorough clean, the tube is the problem. Replacement burners are inexpensive relative to a new grill.

How to Clean Gas Grill Burners (Clogged Ports, Uneven Flames)

Written & researched by Derek Holt Home & Appliances Editor

Updated August 2026

Wide view of a person grilling vegetables, in warm late-afternoon light

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Clean gas grill burners by shutting off and disconnecting the propane, removing the grates, heat tents and burner tubes, clearing each individual port with a stiff wire, brushing along the length of the tube with a brass or nylon brush, checking the venturi for insect nests, then reinstalling and leak-testing with soapy water. Budget 45 to 90 minutes. There is no cost beyond a brush, and it is the single most effective fix for uneven heat, weak flames and a burner that will not light. Do a soapy-water leak test every time you reconnect the gas.

First, read the flames

Before you disassemble anything, take the cooking grates and heat tents off, light all burners on high, and look at the flame pattern. This tells you what you are dealing with.

What you see	What it means
Even ring of blue flames, small yellow tips	Healthy. Clean the exterior and move on.
Dark gaps along the tube	Blocked ports. The core job below.
Flame shooting sideways from one hole	An enlarged or eroded port, often from over-aggressive past cleaning.
Mostly yellow, lazy, sooty flames	Air-to-gas mixture is off. Check the venturi and air shutter.
Flame burning back inside the tube, roaring sound	Flashback. Shut the gas off immediately. Usually a blocked venturi.
Whole burner will not light	Blocked venturi, dead igniter, or a rusted-out tube.

If you see flashback — flame burning inside the tube with a whooshing noise — turn the burner control off and close the tank valve at once, let the grill cool, and do not use it until the venturi is clear.

Over-the-shoulder view of a person grilling vegetables, in soft early-morning light

Tools and materials

An opened paperclip or a burner port cleaning tool
A brass or stiff nylon brush — not steel wool, which leaves fragments
A venturi brush, or a bottle brush that fits the tube diameter
A nut driver or screwdriver for the burner retaining screws or cotter pins
Dish soap, warm water, a spray bottle for the leak test
Gloves and eye protection

Take a photo of the burner assembly before you take anything out. Grills use cotter pins, hooks or screws to retain the tubes, and it is easy to reassemble one a quarter inch off the valve orifice, which causes a yellow flame and poor heat.

The step-by-step clean

Turn all control knobs off, close the tank valve, and disconnect the regulator from the tank. Do not skip this. You will be working directly around the gas orifices.
Let the grill cool fully, then remove the cooking grates and the flavorizer bars or heat tents. Set them aside for a separate wash.
Release the burners. Find the retaining screw, hairpin clip or cotter pin at the back of each tube. Remove it and lift the burner up and back off the valve orifice. The tube simply slides over the orifice; there is no threaded connection.
Clear each port with a wire. Work along the tube, pushing the wire into every hole and pulling it back out. Ports are usually along both sides and sometimes the top. This is tedious — a typical burner has 60 to 120 ports — and it is the part that actually restores an even flame. Do not enlarge the holes.
Brush along the tube, not across it. Run the brass brush lengthwise so debris is pushed off rather than driven into the ports. Cross-brushing packs grit into the holes you just cleared.
Clean the venturi. Look into the open end of the tube that fits over the gas orifice. Spiders are drawn to the mercaptan odorant added to propane and build webs and nests inside these tubes; this is a documented and manufacturer-acknowledged cause of flashback fires. Run a venturi brush or bottle brush all the way through, and shake out the debris.
Check the air shutter. Some burners have an adjustable collar near the venturi opening. Make sure it is clear of grease and set where it was — that ratio sets the flame color.
Optional soak. For heavy grease, soak the tubes in hot soapy water, scrub, rinse, then dry completely. Bone dry, inside and out, or you will be doing this again in a month.
Inspect for failure. Hold the tube up to the light. Holes rusted through the body, cracks, splits along a seam, or metal that flakes when squeezed mean the burner is finished. Replace it rather than reinstalling it.
Clean the firebox while it is open. Scrape grease from the walls down into the grease tray and empty the tray — a full grease tray is the leading cause of grill fires.
Reinstall the burners. Slide each tube fully and squarely over its valve orifice, and confirm the orifice is centered in the opening. Refit the retaining pins or screws. Put the heat tents and grates back.
Reconnect and leak-test. Reattach the regulator hand-tight, open the tank valve slowly with all knobs off, then spray or brush soapy water on every connection. Growing bubbles mean a leak: close the valve, re-seat the connection, and retest. Never test with a flame.
Light and check the flames. One burner at a time. You want that even blue ring. If one section is still dark, that tube needs more port work or replacement.

How often, and what else keeps burners clean

Task	Frequency	Why
Empty grease tray	Every few cooks	Fire prevention, the top priority
Burn off and brush grates	Every cook	Keeps debris off the tents and burners
Clean heat tents / flavorizer bars	2–3 times a season	They shield burners from drippings
Full burner clean	Twice a season, minimum once	Restores even heat
Venturi check	Start of every season, and after storage	Insect nests form while the grill sits
Burner replacement	Every 3–10 years by material	Rust-through is not repairable

Clean heat tents matter more than most owners realize. Their whole purpose is to catch drippings before they land on the burner tubes, so once they are caked and warped, grease goes straight onto the ports and re-clogs them within a few cooks. A full grill clean routine is covered in how to clean a gas grill, and if a tube is beyond saving, replacing gas grill burners walks through the swap.

Over-the-shoulder view of a person grilling vegetables, in bright midday sun

Mistakes that make things worse

Drilling out the ports. Enlarged holes cannot be undone and create a permanent hot spot and yellow flame.
Brushing across the tube. It drives grit into the ports you just cleared.
Using steel wool. Fragments lodge in the ports and rust.
Reinstalling a damp tube. Internal rust reclogs it and can cause delayed ignition, where gas pools and lights all at once.
Skipping the leak test. Any time the tank has been disconnected, soapy water before flame. Every time.
Misaligning the tube on the orifice. A tube sitting slightly off the orifice gives yellow, sooty flames and poor heat, and people blame the burner.

Gas safety, plainly

Propane and natural gas work is where a DIY job stops being casual. Always disconnect the tank before working inside the grill, work outdoors with ventilation, and never use a flame or a lighter to check for leaks. Do not modify, splice or repair a gas hose, regulator or valve — if the hose is cracked, the regulator is failing, or a valve leaks at the body, replace the assembly with the manufacturer part or have a qualified technician handle it. If you smell gas that you cannot trace to a connection you can tighten, shut the tank valve, move the tank clear of the house, and do not light the grill. For a natural gas grill plumbed into the house line, any work on the fixed line itself is licensed work and should be done by a professional; codes covering fuel gas piping are jurisdiction-specific and enforced locally. If you are ever unsure whether a burner is safe to reuse, replace it.

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How to Clean Gas Grill Burners